Azimuthal angle correlations at large rapidities: revisiting density variation mechanism

In the paper we discuss the angular correlation present in hadron-hadron collisions at large rapidity difference ($\bas\,y_{12}\,\gg\,1$). We find that in the CGC/saturation approach the largest contribution stems from the density variation mechanism. Our principal results are that the odd Fourier harmonics($v_{2n+1}$), decrease substantially as function of $y_{12}$, while the even harmonics ($v_{2n}$ ), increase considerably with a growth of $y_{12}$.